#include <stdio.h>
#include <assert.h>
char* my_strcat(char* dest,const char* str)
{
    assert(dest && str);//
    char* ret = dest;
    //while(*++ret);
    while(*ret)
    {
        ret++;
    }
    while(*ret++=*str++);//追加字符串，包含\0
    return dest;
}


int main ()
{
    char arr1[20]="Hello ";
    char arr2[]="World";
    printf("%s\n",my_strcat(arr1,arr2));
    return 0;
}